1. Field of the Invention
My invention relates to positioning jigs for positioning the cutter of plunge routers for the purpose of establishing multiple sets of four holes, each set of four holes consisting of two pair, each pair positioned at the same precise distance from the top or bottom of one of two shelf sides. The holes are for the purpose of accepting pins on which the shelf ends will lay.
2. Description of Prior Art
Bookcases have long been made with height adjustable shelves. One method of achieving height adjustability is to provide a pair of vertical side members, each side member having a double row of holes. Each double row comprises multiple pairs of holes, each pair positioned a given distance from the bottom. When pins or fixtures are placed in two holes in one side member and two corresponding, (positioned at the same distance from the bottom of the respective side member), holes in the other side member, the pins or fixtures provide supports for a shelf. A shelf positioned on such supports will be level front to back and side to side, Typically the pairs of holes will be one inch on vertical centers and be 1/4 inch in diameter to accept short 1/4" dowels.
Though boring jigs are well known, most have been developed for employing hand drills for drilling dowel holes in edges of a work piece. Even with a guide bushing, unskilled users will not be able to drill a hole perfectly perpendicular to the face of the workpiece. Further, most employ infinitely adjustable stops and clamps, so precise measurements must be made by the artisan to ensure correct results. Further, prior art disclosures not only require different size drills for changing hole diameters, but also require different size guide bushings to match different size drills.
Also, prior art disclosures require long jigs to accommodate the long rows of holes required by high shelving. In addition, ordinary twist drills employed in hand drills are not normally capable of drilling clean edged holes of precise diameters in wood, let alone the more difficult-to-drill flake board and laminate, without tearing the surface.
Further, even when a drilling jig is provided with a line of spaced holes having a pitch, there is no provision for providing intermediate holes positioned at exactly one half pitch from the adjoining holes.
Further, none of the guides or jigs have a planar working surface for coacting with the working face of a plunge router.
Also, prior art guides and jigs have a multiplicity of parts and components which are easily lost, costly to produce and whose use is not intuitive, thereby requiring extensive instruction and practice before decent results can be secured.